This is the first renewal of the T32 application from Division of Pediatric Cardiology, Vanderbilt University School of Medicine. By advancing a program that integrates formal training in research on developmental determinants of cardiovascular disease with clinical training in pediatric cardiology, we will provide a unique training environment that will foster development of academic pediatric cardiologists. This training program will not only focus on the molecular and genetic etiologies of congenital heart disease, but will also emphasize the impact of pre- and postnatal development in defining the manifestations of cardiovascular pathology after birth. In addition to trainees in the Pediatric Cardiology, clinical or Ph.D. post-doctoral fellows who have an expressed interest in investigating development mechanisms of cardiovascular disease will be eligible for support. We are requesting continued support for 3 trainees / year for two years for a total of 6 trainees / year for a five year period. This program will provide a unique opportunity for trainees to study the recapitulation of normal developmental processes in the ontogeny of cardiovascular pathology presenting later in childhood or adulthood. The program will be composed of two tracks optimized either for pursuit of preparation for (1) basic science investigation or (2) clinical or translational research. A focused, mentored, laboratory experience with targeted didactic interactions will be tailored to meet the needs of those pursing a more basic science career. For trainees pursuing a career in clinical or translational medicine, the Vanderbilt Master of Science in Clinical Investigation (MSCI) program will be an integral part of the training program. Candidates will be identified from the pool of applicants applying for a pediatric cardiology fellowship (112 applicants for 3 positions in 2017) as well as from talented clinical and post-doctoral fellows throughout Vanderbilt University. During a first clinical year of pediatric cardiology fellowship (PGY-4) the candidates will be matched with mentors and together, they will decide upon a research project. During the second and third years of a four year fellowship, trainees will carry out a mentored research project. During the fourth year, the trainee will complete clinical training with the option of advanced training in a sub-subspecialty as well as continued research and submission of a K08 or K23 application. This grant will provide support for the second and third years of protected research training. The Department of Pediatrics is committed to complete support of fellows during the first and fourth years as well as supplementing support provided by this grant in years two and three. Using the unique strengths of Vanderbilt University in the areas of cardiac development and regeneration, myocardial biology, pulmonary biology and pulmonary hypertension, cardiovascular genetics and pharmacogenomics, vascular biology and atherosclerosis, as well as cardiovascular outcomes based research and bioinformatics, the program will help train the next generation of physician scientists focused on pediatric cardiovascular disease.